Retention of visible implant and visible implant elastomer tags in brown trout in an English chalk stream

Abstract

Retention of both rigid and new soft standard size visible implant (VI) tags in brown troutSalmo trutta after 6 months varied between 42 and 97% for different batches, with no evidence of increased retention of the new type of tag. The 6 month retention of visible implant elastomer tags (VIE) also varied but with a mean of 96%. The VIE retention gradually declined with time up to 42 months.A recent development in fish marking has been the use of tags which are embedded in transparent tissue and obviate many problems of traditional external tags (Farooqi et al., 1995). The usefulness of such tags, however, depends on their retention, but for some of these tags this has not been widely tested, especially in field conditions as opposed to captive fishes. The present study, carried out over several years, investigated the retention of three types of tag in wild brown trout Salmo trutta L. in the River Piddle, a chalkstream in Dorset, England, and assessed their suitability for survival and movement experiments. The tags were rigid and soft visible implant (VI) and visible implant elastomer (VIE) tags (North-west Marine Technology Inc., Shaw Island, WA, U.S.A.).The VI tags are coloured slivers of plastic printed with unique alphanumeric codes which are supplied in two sizes, standard (2Á5 Â 1Á0 mm) and large (3Á5 Â 1Á5 mm). There are two types, a rigid plastic type and a newer soft plastic type. The tag is injected with a supplied injector into the transparent eyelid tissue, immediately behind the eye. The VIE is a fluorescent coloured liquid polymer which is mixed with a catalyst and injected into transparent tissue (e.g. eyelids and webbing between fin rays) with a syringe and it cures to a rubbery consistency after some hours. While the VI tag is intended for identification of individual fish, the VIE is generally used for batch marking.

Visible Implant Elastomer (VIE) Tags for Marking Small Rainbow Trout

“…However, in those studies the external calcein mark disappeared very rapidly in tanks exposed to direct sunlight. Visible implant elastomer tags are not sensitive to direct sunlight, and they have been successfully used for long-term (6-42-month) capture-recapture studies in the wild (Summers et al 2006). Thus, VIE tags may also be an alternative for mass marking young and small fish.…”

Roles of discharge and temperature in recruitment of a cold‐water fish, the European grayling Thymallus thymallus, near its southern range limit

“…Sampling was completed by hand-held, single anode electric fishing, with between three and five passes completed per site until the depletion in captured grayling was ≥ 50% between the final two passes. VI tags were used for age 1+ grayling as they would potentially lose a PIT tag during spawning (Summers, Roberts, Giles, & Stubbing, 2006). The Wylye fish community is highly dominated by salmonids and predominantly grayling and trout, but salmon and Eurasian dace Leuciscus leuciscus are rarely captured.…”

“…All tagged grayling also had their adipose fin removed, to ensure recaptures could be identified despite potential tag loss, and a scale sample taken for age validation, with a minimum number of three scales taken between the dorsal fin and lateral line. VI tags were used for age 1+ grayling as they would potentially lose a PIT tag during spawning (Summers, Roberts, Giles, & Stubbing, 2006). Following recovery to normal swimming behaviour, all fish were returned alive to the site of their capture.…”

Evaluation of VIE (Visible Implant Elastomer) and PIT (Passive Integrated Transponder) physical tagging systems for the identification of red porgy fingerlings (Pagrus pagrus)

“…Time, as already mentioned, plays a crucial role. Although tags can be observed in some fish for as long as after 6 months (Dewey and Zigler 1996;Summers et al 2006;Brennan et al 2007) or even after more than 3 years (Willis et al 2001), in general, it is after 3 months (long-term tagging) that the tag loss rate increases (Doupé et al 2003;Goldsmith et al 2003;Fryda et al 2007;Josephson and Robinson 2008;Zeller and Cairns 2010). Also the fish species and the placement of the tag determine the tag loss rate (Close and Jones 2002;Brennan et al 2007;Bolland et al 2009;Reeves and Buckmeier 2009).…”